Adaptive Backbone-Based Multicast Protocol for Ad Hoc Networks
Basics of Mobile Ad hoc Networks MANET Applications MANET Mobile Ad hoc NETworks
Homogeneity Multiple-hop Wireless communication Mobility Exhaustible energy Lack of infrastructure
Medium Access Control Protocols for Ad hoc Networks Problems in Wireless Channel Access
The hidden terminal problem two nods are hidden from each other when both attempt to transmit to the same receiving node (collision occurs at receiver) Problems in Wireless Channel Access Using RTS/CTS handshake to resolve the hidden
terminal problems Problems in Wireless Channel Access The incompleteness of the RTS/CTS protocol RTS/CTS sent by different nodes may still collide
Problems in Wireless Channel Access Another RTS/CTS problem scenario multiple CTS are granted to different neighboring nodes Problems in Wireless Channel Access
The exposed terminal problem overhearing a transmission from neighboring node can inhibit a node from transmitting to other nodes Problems in Wireless Channel Access Solutions to exposed terminal problem - directional antenna
and separate data/control channels MACA (Multiple Access with Collision Avoidance) RTS/CTS handshake without carrier sensing Per-packet transmission power control inhibit a transmitter when a CTS is overheard If node A has been sending data to node B for some
time, A would know how much power it needs to reach B If A overhears Bs response to an RTS (i.e., a CTS) from another node D, A could lower its power and communicate with C B A
D C DBTMA Dual Busy Tone MA Two out-of-band busy tones are used to notify neighboring
nodes of any on-going transmission BTt a node is transmitting on the data channel BTr a node is receiving on the data channel To transmit, sense BTr. If no BTr, send RTS Upon receiving RTS, receiver senses BTt. If no BTt, send CTS and raise BTr Continuous busy tones are crucial to deal with mobility
Unicast Routing Protocols for Mobile Ad hoc Networks Categorization of Ad Hoc Routing Protocols Ad Hoc On-Demand Distance Vector (AODV)
Use destination sequence # to prevent loops and ensure fresh route information Establish reverse pointer (path) via RREQ Establish forward route entry (path) via RREP over reverse path Assume symmetric links
Dynamic Source Routing (DSR) Each data packet sent by the source has to contain complete source route information Location-Aided Routing (LAR)
Assume the location and speed of the destination node are known Concepts of request zone and expected zone and consideration of
route physical distance Specify the request zone in RREQ to contain propagation Power-Aware Routing (PAR) Remaining battery life is used as the primary routing metric select routes that have a longer overall battery
life Zone Routing Protocol (ZRP) Hybrid approach proactive (intra-zone) and on-demand (inter-zone) Border nodes (via bordercast) perform on-demand route
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